Martin Wolf
The IceCube Neutrino Observatory.
The IceCube Neutrino Observatory is run by an international group of scientists.
This fall, as temperatures plummet to -50°C (or -58°F) at the South Pole, a team of UW-Madison scientists and engineers will embark on an adventure to the frozen desert. Their goal: drill seven holes through a mile and a half of Antarctic ice to complete a revolutionary upgrade to the world’s coldest neutrino telescope.
“Whoever had the idea of drilling holes a mile and a half into a glacier was crazy,” says Vivian O’Dell, project manager for the IceCube Upgrade. “Completely nuts. And yet it works.”
It’s imperative the work gets done in the three short months they will be there because the researchers will be unable to return. This is partly due to limited funding by the National Science Foundation (NSF). Additionally, staff at the Amundsen-Scott South Pole Station, where the research is being conducted, will switch priorities after this field season to upgrading infrastructure and supporting other science teams.
The IceCube Neutrino Observatory, operated by an international group of scientists called the IceCube Collaboration, represents an ambitious physics experiment to discover more information about a particle that is not very well understood. Unlike traditional telescopes that detect light, IceCube uses one cubic kilometer of the Antarctic ice sheet to catch ghostly particles called neutrinos streaming through the cosmos.
“We’re actually looking at neutrinos, which are produced similarly to photons in interactions in stars and planets,” O’Dell says, comparing neutrinos to light particles. But unlike light, which gets bent and distorted as it travels through space, neutrinos take a direct path.
“When a neutrino comes, you can almost guarantee that it came on the same trajectory it was produced on,” O’Dell continues. This unique property makes neutrinos perfect cosmic messengers, carrying information directly from the most violent events in the universe — exploding stars, black holes, and gamma-ray bursts.
“It is the study of particle physics and astrophysics, the nature of the universe, and the origin of high energy cosmic rays that drives this research forward,” O’Dell says. She points out that the study of particle physics by Tim Berners-Lee gave rise to the world wide web as a mechanism for scientists to communicate with each other. And today, the internet is a part of virtually everyone’s daily life.
“Advancing the study of particle physics and astronomy has allowed us to harness much of the scientific principles we learn or develop new mechanisms for analyzing the data, which in turn has always resulted in economic gains,” O’Dell says.
The discovery that neutrinos can change from one type to another changed particle physics. “What we knew about neutrinos up until about 25 years ago was that neutrinos were completely massless and traveled at the speed of light,” O’Dell explains. But scientists discovered that one type of neutrino could transform into another — something that’s only possible if neutrinos have mass, even if incredibly tiny. “You can only do that if you have mass,” she notes.
Drilling into the ice
The detector itself is a marvel of engineering. UW-Madison is the lead institution for the project, coordinating what amounts to a cubic kilometer of instrumented ice. Buried deep beneath the surface, thousands of optical sensors detect the faint flashes that erupt when neutrinos interact with the ice.
The upcoming Upgrade will push IceCube’s capabilities even further. “The Upgrade detector is designed to measure exactly how much one kind of neutrino turns into another kind of neutrino,” O’Dell says. This will make IceCube far more sophisticated at studying fundamental neutrino properties.
Making this Upgrade happen requires overcoming extraordinary engineering challenges. Terry Benson, a mechanical engineer at UW’s Physical Sciences Laboratory, will return to drilling operations for his 12th Antarctic deployment.
Benson is on a team of 28 people working in three shifts around the clock, with additional crews handling detector installation and commissioning.
The team uses a massive hot water drilling system that consumes five megawatts of power — enough to supply a neighborhood. “Most of that power is put into hot water that’s delivered to a nozzle, and that’s how we drill the hole,” Benson explains. The system can drill a 60-centimeter diameter hole to depths of 2.5 kilometers in just 31 hours. “In order to save fuel, we made the system bigger and more powerful. The less time we spend in the ice drilling the holes, the more fuel we save.”
Time is crucial here — the holes begin freezing almost immediately after drilling.
“You drill the hole and immediately water starts freezing in the hole,” O’Dell explains. “So you have to make the hole bigger than you want it because you have to have time to put the detector in.” The team is aiming for each deployment to take at least 24 hours, racing against the Antarctic ice.
Life at Pole
The physical demands are extreme. At 9,300 feet altitude in one of the world’s driest, coldest environments, workers burn massive calories just to stay warm. “The air is thin, it’s very dry, and you’re working hard,” Benson says. “You can just eat and eat and eat…and still lose weight,” Temperatures will range from -50°C when the first crews arrive in October to a relatively balmy -20°C (or -4°F) in December.
Yet despite the harsh conditions, both scientists speak fondly of their South Pole experiences. The research station offers surprising amenities — good food, a gymnasium, even a pool table — and fosters an extraordinary sense of community among the international team of researchers.
“The people we work with — the Antarctic contractors — are just top-notch,” O’Dell says. “When something doesn’t work, they don’t go, ‘Well, there’s no Home Depot, so I guess we can’t get that part.’ They totally MacGyver really well.”
Benson echoes this sentiment, noting how the extreme environment creates lasting bonds. “The original IceCube team (from 2004-2010) still go to each other’s weddings, and when they’re vacationing in other countries, they spend time at their houses. Lifelong bonds for sure.”
The IceCube Collaboration, with over 450 scientists in 58 institutions from 14 different countries, runs an extensive model for neutrino astronomy research. The upcoming Upgrade represents years of preparation and international coordination.
The project also supports unexpected scientific discoveries along the way. As they drill, the team will collect water samples for microbiologists studying whether life exists in the deep ice. They’ve even installed seismometers in collaboration with the U.S. Geological Survey to monitor earthquakes from deep within the Antarctic ice sheet.
High hopes
Previous drilling seasons have yielded their own surprises. Last year, the team discovered a parachute buried 50 feet down, likely from supply drops decades ago. “We were like, ‘Oh, there’s something weird and green down there,’” O’Dell recalls.
Such moments of levity help balance the immense pressure of the mission. With no possibility of returning to the Antarctic — even if they do not fulfill their mission — every decision matters.
But both scientists express confidence in their teams and preparation. Years of planning, international collaboration, and cutting-edge engineering have led to this moment. As they prepare for their departure to the South Pole, they carry with them aspirations and hopes of pushing the boundaries of human knowledge about the cosmos.
Says O’Dell: “Being at [the] Pole is very different from solving problems anywhere else.”
[Editor's note: The original headline on this story incorrectly referred to this expedition as the project's final expedition to Antarctica. Researchers do hope to continue their work at the IceCube Neutrino Observatory.]
